Well cap rod hanger

ABSTRACT

A well cap rod hanger for securing a well head having an upper portion adapted to be attached to a rod elevator, a body having a lower cylindrical portion with a threaded outer surface adapted to be threadedly attached to the inside diameter of a well head, and a second cylindrical portion extending downward from the body, the second cylindrical portion adapted to be threadedly attached to a rod string.

FIELD OF THE INVENTION

The present invention relates generally to the servicing and sealing ofoil or gas wells. More particularly, the present invention relates towell caps for attachment to a well head.

BACKGROUND OF THE INVENTION

An oil or gas well can be secured (to maintain well control) by having astuffing box attached to the well head. A series of interconnected rods,the rod string, begins at the well head and extends down to eitherconnect to the oil pump, which lies below the earth's surface where thehydrocarbon-bearing formation is found, or to reach the gas reservoir.Attached to the top of the uppermost rod is a polished rod, which runsthrough the stuffing box. The smooth surface of the polished rod allowsefficient hydraulic seals to be formed around the reciprocating orrotating rod string.

When servicing the well, the stuffing box and polished rod are removedto allow access to the rod string. Rods may be removed to service thewell and its components. While the stuffing box and polished rod areremoved from the rod string, rod elevators support the weight of the rodstring. A rod elevator is a lightweight elevator designed for runningand retrieving the rod string in wells equipped with a rod pump. Rodelevators can be used on a service rig or a rod unit specificallydesigned for running and retrieving rod strings. The elevator is notdesigned to secure the well head if the well was to become pressurized.

Radigans may or may not be present on the well head. A radigan is asemi-circular rubber clamp seated inside the well head. The radigans canbe closed to prevent a blow out if the well pressure rises quickly andfunction by closing around a rod to close the hole. Thus, radigans maybe used to secure a well head only if there are rods running through thewell head, and if pressure in the well quickly rises (which may lead toa blow out), the polished rod and stuffing box must be quickly attachedto the well head before the well can be secured. Even once the polishedrod and stuffing box are in place, closing the radigans takes severalminutes. The usefulness of using radigans to secure the well is furtherlimited in that radigans will not permanently secure the well, theradigans must be built to a size that is compatible with a given rodstring to secure a well to the extent that they can, and radigans cannotsupport the weight of the rod string.

The stuffing box and polished rod must be attached to the rod stringusing rod elevators. This process can take several minutes because thestuffing box and polished rod are heavy (can weigh 136 kg/300 lb) andextremely difficult to handle (9 m/30 ft long). The current techniquesto temporarily secure the stuffing box and polished rod to the well headand rod string, to secure the well, can be dangerous when working underpressure. Often, the stuffing box and polished rod need to be quicklyattached to the well head and rod string to secure the well. A quickchange in weather conditions (rain, hail, lightning, high winds, etc.)can make working conditions dangerous, thus securing the well quicklyand safely becomes extremely important. Thus, hydrocarbon spills duringa blow out can often only be controlled as quickly as the workers canattach the stuffing box and polished rod to the well head and rodstring.

A well cap is a is a threaded piece of steel that attaches to the wellhead to secure the well. Previous well caps cannot be used to secure awell head while rods are present in the well.

U.S. Pat. No. 4,467,871 issued to Rollwitz teaches a clamp-based rodstand that attaches to a polished rod by encirclement and holds it abovethe well head, thus freeing up the pumpjack. The invention taught byRollwitz does not assist in securing the well.

U.S. Pat. No. 4,850,736 issued to Petrie teaches a rod clamp thatfacilitates servicing of an oil well, reduces the likelihood of a rodstring falling into the inground portion of the well, and minimizesscarring of polished rods by eliminating the need to reposition. Theinvention taught by Petrie does not assist in securing the well.

Given the difficulty, danger, and wastage experienced while securing awell head with a stuffing box and rod string, it is desirable to providea device to facilitate the servicing and securing of a well or rodstring.

SUMMARY OF THE INVENTION

It is an object of the present invention to obviate or mitigate at leastone disadvantage of previous method and apparatus for temporarilysecuring a rod string and well head.

In a first aspect, the present invention provides a well cap rod hangerfor securing a well head having an upper portion adapted to be attachedto a rod elevator, a body having a lower cylindrical portion with athreaded outer surface adapted to be threadedly attached to the insidediameter of a well head, and a second cylindrical portion extendingdownward from the body, the second cylindrical portion adapted to bethreadedly attached to a downhole implement.

In one embodiment, the upper portion including a head and a neck, thehead having a greater outer dimension than the neck, and a taperedportion between the head and the neck.

In one embodiment, the well cap rod hanger further includes a taperedportion between the head and the neck.

In one embodiment, the downhole implement includes a rod string. In oneembodiment, the downhole implement includes a measuring device. In oneembodiment, the measuring device includes a down hole recorder.

In a further aspect, the present invention provides a method of securinga well having a well head, including providing a well cap rod hangerhaving an upper portion adapted to be attached to a rod elevator, a bodyhaving a lower cylindrical portion with a threaded outer surface adaptedto be threadedly attached to the inside diameter of a well head, and asecond cylindrical portion extending downward from the body, the secondcylindrical portion adapted to be threadedly attached to a rod string,connecting the rod string and the second cylindrical portion, andconnecting the lower cylindrical portion to the well head, wherein thewell head is secured with the rod string within the well.

In one embodiment, a fluid tight seal is formed between the lowercylindrical portion and the well head.

In one embodiment, the method includes lowering the rod string and thewell cap rod hanger using the elevator until the lower cylindricalportion is at the well head.

In a further aspect, the present invention provides a well cap rodhanger for securing a well head having an upper portion, having a headand neck, the upper portion adapted to be attached to a rod elevator, abody having a gripping portion and a lower cylindrical portion, thelower cylindrical portion having a threaded outer surface adapted to bethreadedly attached to the inside diameter of a well head, and a secondcylindrical portion extending downward from the body, the secondcylindrical portion adapted to be threadedly attached to a rod string.

Other aspects and features of the present invention will become apparentto those ordinarily skilled in the art upon review of the followingdescription of specific embodiments of the invention in conjunction withthe accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofexample only, with reference to the attached Figures, wherein:

FIG. 1 is a schematic of a well cap rod hanger of the present invention;and

FIG. 2 is a schematic of the well cap rod hanger of FIG. 1 in use with awell head, a rod string, and a rod elevator.

DETAILED DESCRIPTION

Generally, the present invention provides a well cap rod hanger fortemporarily securing a well head or well head and a rod string.Alternatively, a well head can be secured and a device intended todepend into the well, such as a measuring device, may be attached to theapparatus.

Referring to FIG. 1, a well cap rod hanger 10 in accordance with thepresent invention includes a head 20, a tapered shoulder 30, and a neck40. The head 20, a tapered shoulder 30, and a neck 40 collectivelycomprise the upper portion 45. The upper portion 45 is adapted to beattached to a rod elevator 100 (FIG. 2) (or other lifting means, such asa crane or travelling block etc. known to one skilled in the art),preferably through grasping by the rod elevator, so that the rodelevator 100 may be used to support the rod string 90 and move the wellcap rod hanger 10 up/down to move the rod string 90 in/out of the well.The tapered shoulder 30 is to hold a rod elevator 100, the width of theneck 40 is narrow enough to be grasped by the rod elevator 100 and thelength of the neck 40 is preferably equal to or greater than the graspof the rod elevator 100. The head 20 and the neck 40 are each preferablycylindrical in shape.

The well cap rod hanger 10 also includes a tapered shoulder 50 and abody 60, the body 60 having a threaded lower portion 65 adapted to bethreadedly attached to the interior of a well head 80 (FIG. 2). Thetapered portion 50 is between the neck 40 and a body 60. The body 60 ispreferably cylindrical in shape. The tapered shoulder 50, the body 60,and the threaded lower portion 65 collectively comprise the lowerportion 67. The pin 70 has a threaded surface 75 adapted to bethreadedly attached to the a rod string 90 (FIG. 2).

The upper portion 45 may be integral to the lower portion 67, or theupper portion 45 and the lower portion 67 may be separate componentsadapted to be attached to each other. Similarly, the pin 70 may beintegral to the lower portion 67, or the pin 70 may and the lowerportion 67 may be separate components adapted to be attached to eachother.

The upper portion 45 may be any type of contact point that can besecurely grasped by the rod elevator 100. For example, rather thancomprising the head 20, tapered shoulder 30, and neck 40, or somecombination of those components, the portion of the well cap rod hanger10 above the lower portion 67 may be a hook, clevis, eye, or otherattachment means known to one skilled in the art.

Referring to FIG. 2, the well cap rod hanger 10 is depicted with thewell head 80 and the rod string 90. The rod elevator 100 grasps theupper portion 45 and the well cap rod hanger 10 is lowered into positionsuch that the threaded lower portion 65 can be secured to the well head80 and that the pin 70 can be secured to the rod string 90. To securethe well cap rod hanger 10 to the well head 80 and to the rod string 90,the threaded lower portion 65 is threadedly attached to the well head 80and the pin 70 is threadedly attached to the rod string 90. The threadedlower portion 65 and the pin 70 can be threadedly attached to the wellhead 80 and rod string 90, respectively, through use of a pipe wrench,which may grip the preferably cylindrical body 60, and the rod string90, respectively. The threaded lower portion 65 and threaded surface 75are threaded in the same orientation, allowing them to be tightened orloosened in the same direction to threadedly attach the well cap rodhanger 10 to the well head 80 and rod string 90.

Alternatively, the pin 70 may be first threadedly attached to the rodstring 90 while the well cap rod hanger 10 is grasped by the rodelevator 100 while the rod string is suspended above the well head 80.The welt cap rod hanger 10 and rod string 90 are then lowered togetherby the rod elevator to allow the lower portion 65 to be threadedlyattached to the well head 80, forming a fluid seal.

Once the pin 70 is threadedly attached to the rod string 90 and thethreaded lower portion 65 is attached to the well head 80, the rodelevator 100 can be released because the well cap rod hanger 10 isbearing the weight of the rod string 90. The well cap rod hanger 10 alsosecures the well head 80 because it is threadedly sealingly attached tothe well head 80.

To remove the well cap rod hanger 10, the threaded lower portion 65 andthe pin 70 are respectively disengaged from the well head 80 and fromthe rod string 90. The well cap rod hanger 10 is then removed from thewell head 80. Removal of the well cap rod hanger 10 from the well head80 is possible by using a pipe wrench to disengage the threaded lowerportion 65 and the pin 70 from the well head 80 and the rod string 90,respectively.

The threaded portion lower portion 65 and pin 70 may be constructed withvarious diameters, the respective diameters being selected to create awell cap rod hanger 10 that is compatible with a given well head and rodstring.

In addition to sealing a well, the invention herein described may beused to suspend a rod string. When a well is abandoned or put off line,the typical practice is to back off the polished rod and let the rodstring sit on the bottom of the well. In this case, the rod string willbend and the pump can seize. The invention herein described can be usedto suspend the rods in the tubing so they can be used at a later date. Atypical rod string and pump can cost up to $20,000. The invention hereindescribed may also be used to suspend any downhole tool within a casingor production tubing.

In the preceding description, for purposes of explanation, numerousdetails are set forth in order to provide a thorough understanding ofthe embodiments of the invention. However, it will be apparent to oneskilled in the art that these specific details are not required in orderto practice the invention.

The above-described embodiments of the invention are intended to beexamples only. Alterations, modifications and variations can be effectedto the particular embodiments by those of skill in the art withoutdeparting from the scope of the invention, which is defined solely bythe claims appended hereto.

What is claimed is:
 1. A well cap rod hanger for securing a well headcomprising: an upper portion adapted to be attached to a rod elevator; abody having a lower cylindrical portion with a threaded outer surfaceadapted to be threadedly attached to the inside diameter of a well head;and a second cylindrical portion extending downward from the body, thesecond cylindrical portion adapted to be threadedly attached to adownhole implement.
 2. The well cap rod hanger of claim 1, the upperportion including a head and a neck, the head having a greater outerdimension than the neck, and a tapered portion between the head and theneck.
 3. The well cap rod hanger of claim 2 further comprising a taperedportion between the head and the neck.
 4. The well cap rod hanger ofclaim 1, the downhole implement comprising a rod string.
 5. The well caprod hanger of claim 1, the downhole implement comprising a measuringdevice.
 6. The well cap rod hanger of claim 5, the measuring devicecomprising a down hole recorder.
 7. A method of securing a well having awell head, comprising: a. providing a well cap rod hanger having: anupper portion adapted to be attached to a rod elevator; a body having alower cylindrical portion with a threaded outer surface adapted to bethreadedly attached to the inside diameter of a well head; and a secondcylindrical portion extending downward from the body, the secondcylindrical portion adapted to be threadedly attached to a rod string;b. connecting the rod string and the second cylindrical portion; and c.connecting the lower cylindrical portion to the well head, wherein thewell head is secured with the rod string inside the well.
 8. The methodof claim 7, wherein a fluid tight seal is formed between the lowercylindrical portion and the well head.
 9. The method of claim 7, furthercomprising lowering the rod string and the well cap rod hanger using theelevator until the lower cylindrical portion is at the well head.
 10. Awell cap rod hanger for securing a well head comprising: an upperportion, having a head and neck, the upper portion adapted to beattached to a rod elevator; a body having a gripping portion and a lowercylindrical portion, the lower cylindrical portion having a threadedouter surface adapted to be threadedly attached to the inside diameterof a well head; and a second cylindrical portion extending downward fromthe body, the second cylindrical portion adapted to be threadedlyattached to a rod string.